# Do gravitational waves carry energy?

We now know that gravitational waves are real. Do they carry energy? I mean thy are waves and every wave carries energy.

If they carry energy, how do they do it?

Is there any equation to describe it?

• Best source i know of to understand this is Weinberg’s book, Gravitation and Cosmology, section on gravitational waves. He derives an equation for the power per unit solid angle into gravitational waves given a classical source with an energy momentum tensor. – Wakabaloola Feb 20 '18 at 7:41
• @Wakabaloola Can you give me something from Internet? – Theoretical Feb 20 '18 at 8:56
• i don’t know of any other source that is as complete and clear as Weinberg’s, might be worth googling. maybe somebody else can offer some other source material too (?) – Wakabaloola Feb 20 '18 at 9:02
• A gravitational wave will cause the distance between two test masses to oscillate. A local observer will detect this as an input of kinetic energy into the masses. Wald has a thorough discussion in sec. 4.4, pp. 84-86. For a freely available treatment, see Carroll, arxiv.org/abs/gr-qc/9712019 , ch. 6. – Ben Crowell Feb 21 '18 at 5:52
• @BenCrowell Can anyone measure this kinetic energy using equations? – Theoretical Feb 21 '18 at 6:30

Yes they do. They do this in the form of ripples. They distort the fabric of space time. They carry energy in the form of waves . Just like the type of distortion you can see in a mat when you form waves in it. However it ( mat ) has energy and you can see it. Same in the case of gravitational waves , they carry energy in the form of ripples , or waves .